The control valve cannot be closed even when fully open
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To avoid affecting the unit’s efficiency, the control valve of the turbine cannot be closed. I believe that the main steam valve can be used to ensure the proper start-up and shutdown of the turbine, while waiting for a major maintenance period to replace the control valve. Please offer some advice!
The conditions under which starting the turbine is prohibited clearly state that the turbine must not be started if there is a malfunction in the speed control system! Since the equipment driven by the turbine is prone to sudden load loss or abnormal operating conditions, which can easily lead to the turbine speeding up or even running away, the main steam valves are generally electric; it takes some time for them to open or close, which does not meet the requirements for regulating the turbine’s speed. Furthermore, if there is internal leakage in the electric isolators and the main steam valves, the turbine will accelerate automatically or fail to stop, leading to more serious accidents. Doing this not only fails to bring any benefits but also increases the risk level.
The conditions under which starting the turbine is prohibited clearly state that the turbine must not be started if there is a malfunction in the speed control system! Since the equipment driven by the turbine is prone to sudden load loss or abnormal operating conditions, which can easily lead to the turbine speeding up or even running away, the main steam valves are generally electric; it takes some time for them to open or close, which does not meet the requirements for regulating the turbine’s speed. Furthermore, if there is internal leakage in the electric isolators and the main steam valves, the turbine will accelerate automatically or fail to stop, leading to more serious accidents. Doing this not only fails to bring any benefits but also increases the risk level.
The conditions under which starting the turbine is prohibited clearly state that the turbine must not be started if there is a malfunction in the speed control system! Since the equipment driven by the turbine is prone to sudden load loss or abnormal operating conditions, which can easily lead to the turbine speeding up or even running away, the main steam valves are generally electric; it takes some time for them to open or close, which does not meet the requirements for regulating the turbine’s speed. Furthermore, if there is internal leakage in the electric isolators and the main steam valves, the turbine will accelerate automatically or fail to stop, leading to more serious accidents. Doing this not only fails to bring any benefits but also increases the risk level.
For safety reasons, it’s better to replace it right away
I have encountered this situation before: the connecting bolts between the valve stem of the control valve and the butterfly valve came loose and got stuck inside the butterfly valve, which caused the control valve to be able to open but not to close